Tractor



FIG. 1 is a right-side elevation view of a tractor that has the design.

FIG. 2 is a top plan view of the tractor.

FIG. 3 is a left-side elevation view.

FIG. 4 is a front elevation view; and,

FIG. 5 is a back elevation view.

The broken lines represent unclaimed elements of the tractor, and do not form part of the claimed design. 

CLAIM The ornamental design for an tractor, as shown and described. 